<li id="search">
    <form method="get" id="searchform" action="<?php bloginfo('url'); ?>">
        <div>
            <input type="text" id="s" name="s" class="searchinput" value="Search" onfocus="if (this.value == 'Search') {this.value = '';}" onblur="if (this.value == '') {this.value = 'Search';}" />
            <input style="display:none;" type="submit" id="searchsubmit" value="<?php echo attribute_escape(__('Search')); ?>" />
        </div>
    </form>
</li>